Search results for "Illusions"
showing 10 items of 50 documents
Op art et roman virtuel : correspondances entre Escher et Perec
2012
Op art et roman virtuel : correspondances entre Escher et Perec Les structures mathématiques, la notion de réalité comme « humaine illusion », le défi à l’infini et la structure énigmatique qui donne aux œuvres eschériennes la même structure que celle d’un roman policier permettent d’établir des convergences significatives entre le graveur hollandais et Georges Perec. Dans certaines œuvres de Perec, en effet, il est possible de remarquer des références explicites au graveur bien qu’elles constituent la traduction visuelle de l’angoisse du « retour du semblable », du « retour involontaire au même point ». Mais Perec ne se limite pas seulement à citer Escher, puisque certaines de ses œuvres c…
Visually produced locomotion in an autokinetic setup.
1987
On individual ttials, 15 subjects stood G m before a minicomputer screen displaying a colon in a completely darkened room Subjects were aware that the light source wzs stationary. They were instructed to fixate the colon and to perform nonlocomotive jogging in place for 2 min. and continuously to report their sensations. Room lights were turned on after 30 sec., and subjects' deviations from their starting places were measured. All subjects had moved toward the light source (M = 4.42 m, SD = .43) although they were convinced that they had not moved. Instead, they had reported either the light source approached them or the light source became larger and/or more intense. On a second trial, su…
The illusion of contact: Insights from Winnicott’s 1952 letter to Klein
2021
Using Winnicott’s theory, this article produces an account of the individual’s relation to a given conceptual framework. Whereas Winnicott’s ideas have been almost exclusively discussed in developmental and psychopathological contexts, the present article extends Winnicott’s theory and applies it to the problem of interpersonal understanding. Taking a lead from one of Winnicott’s letters to Klein, the article investigates the problem of expressing one’s idiosyncratic insights in the confines of a given conceptual framework. The article examines Winnicott’s theory of compliance and creativity, discusses the plea that Winnicott makes to Klein, analyses the encounter with a “dead language”, an…
White Noise Speech Illusions: A Trait-Dependent Risk Marker for Psychotic Disorder?
2019
Supported by the European Community’s Seventh Framework Program under grant agreement No. HEALTH-F2-2009-241909 (Project EU-GEI)
Full-body illusions and minimal phenomenal selfhood.
2008
We highlight the latest research on body perception and self-consciousness, but argue that despite these achievements, central aspects have remained unexplored, namely, global aspects of bodily self-consciousness. Researchers investigated central representations of body parts and actions involving these, but neglected the global and unitary character of self-consciousness, the ‘I’ of experience and behaviour. We ask, what are the minimally sufficient conditions for the appearance of a phenomenal self, that is, the fundamental conscious experience of being someone? What are necessary conditions for self-consciousness in any type of system? We offer conceptual clarifications, discuss recent e…
Eye position tunes the contribution of allocentric and egocentric information to target localization in human goal-directed arm movements.
1997
Subjects were required to point to the distant vertex of the closed and the open configurations of the Muller-Lyer illusion using either their right hand (experiment 1) or their left hand (experiment 2). In both experiments the Muller-Lyer figures were horizontally presented either in the left or in the right hemispace and movements were executed using either foveal or peripheral vision of the target. According to the illusion effect, subjects undershot and overshot the vertex location of the closed and the open configuration, respectively. The illusion effect decreased when the target was fixated and when the stimulus was positioned in the right hemispace. These results confirm the hypothe…
Somatosensory Illusions Elicited by Sham Electromagnetic Field Exposure: Experimental Evidence for a Predictive Processing Account of Somatic Symptom…
2020
OBJECTIVE According to the predictive processing theory of somatic symptom generation, body sensations are determined by somatosensory input and central nervous predictions about this input. We examined how expectations shape predictions and consequently bodily perceptions in a task eliciting illusory sensations as laboratory analogue of medically unexplained symptoms. METHODS Using the framework of signal detection theory, the influence of sham Wi-Fi on response bias (c) and somatosensory sensitivity (d') for tactile stimuli was examined using the somatic signal detection task (SSDT). A healthy student sample (n = 83) completed the SSDT twice (sham Wi-Fi on/off) in a randomized order after…
Imaging the visual autokinetic illusion with fMRI
2005
During fixation of a stationary, dim light-emitting diode (LED) in complete darkness, a subtle, apparent motion is perceived which is called autokinesis. This autokinetic illusion increases with increasing fixation time. Eleven healthy subjects were examined by fMRI while fixating an LED in darkness for 35 s. BOLD signal changes of the first and the second half of the fixation period were compared. While the stimulus was the same for both periods, perception differed in that autokinesis was more pronounced in the second half. This second half of the period was associated with bilateral activations in the motion-sensitive middle occipito-temporal area known as MT/V5. Our finding suggests tha…
Titchener's T with flanks.
2018
Abstract Flanks were added to Titchener's (1901) T-illusion figure to test its susceptibility to context stimuli. The addition of a second divided line yielded H-type figures, and the addition of a second undivided line, +-type figures. The lengths of the Ts' undivided lines was expected to be overestimated relative to the lengths of the divided lines, when all lines were about equally long, and the illusion was expected to become smaller when one or two gaps had been introduced between the lines. Results conformed to the predictions. The amount of illusion was larger for the no-gap H than the T, and was almost annihilated with the two-gaps H, with 3 out of 14 observers showing an inverse r…
On the interpretation of optical illusions.
1973
If excited by stimuli adjacent in space and time, the optical system frequently perceives illusions in the form of apparent movements. These effects may be attributed to the dynamic properties of the retinal nerve nets. On the basis of a specific psychophysical experiment the mechanism underlying the generation of optical illusions is interpreted by the methods of systems theory and its use in systems analysis is discussed. It is shown that for the perception of apparent movements the transit times of the signals in the dendrites are particularly important.